Field of the Invention
The present invention relates to a film cooling structure in which injection ports are provided on a wall surface facing a high-temperature gas passage, such as a rotor blade, a stator blade, and an inner tube of a combustor in a gas turbine engine, and cooling of the wall surface is performed by causing a cooling medium injected from the injection ports to flow along the wall surface.
Description of Related Art
Conventionally, many injection ports are provided on a wall surface such as a rotor blade in a gas turbine engine (hereinafter simply referred to as “gas turbine”) such that the injection ports are oriented in the same direction. A film flow of a cooling medium such as air injected from these injection ports cools the wall surface, which is exposed to a high-temperature gas. As such a film cooling structure, a structure has generally been proposed in which a round hole is provided in a wall so as to be inclined toward a downstream side of a high-temperature gas, and a cooling medium is injected from an oval injection port opened at the surface of the wall. However, cooling efficiency of this cooling structure is poor. Therefore, improved cooling structures, such as a structure in which an injection port for jetting a cooling medium to a wall surface has a bilobed shape (Patent Document 1) and a structure in which a distribution portion is provided between a pair of injection ports (Patent Document 2), have been known.